Cortical Networks Relating to Arousal Are Differentially Coupled to Neural Activity and Hemodynamics.

Even in the absence of specific sensory input or a behavioral task, the brain produces structured patterns of activity. This organized activity is modulated by changes in arousal. Here, we use wide-field voltage imaging to establish how arousal relates to cortical network voltage and hemodynamic activity in spontaneously behaving head-fixed male and female mice expressing the voltage-sensitive fluorescent FRET sensor Butterfly 1.

Biomechanical Evaluation of TensionLoc Versus the Double Spike Plate for ACL Graft Tibial Fixation.

Background: The optimal tibial fixation of anterior cruciate ligament (ACL) reconstruction (ACLR) grafts remains controversial.

Purpose/hypothesis: The purpose of this study was to compare the biomechanical characteristics of the TensionLoc (TL) cortical fixation device with the Double Spike Plate (DSP) fixation device for ACL tibial fixation using both bone-patellar tendon-bone (BTB) and quadriceps grafts. It was hypothesized that there would be no differences in biomechanical characteristics between the fixation devices regardless of graft type.

Thalamic bursting and the role of timing and synchrony in thalamocortical signaling in the awake mouse.

The thalamus controls transmission of sensory signals from periphery to cortex, ultimately shaping perception. Despite this significant role, dynamic thalamic gating and the consequences for downstream cortical sensory representations have not been well studied in the awake brain. We optogenetically modulated the ventro-posterior-medial thalamus in the vibrissa pathway of the awake mouse and measured spiking activity in the thalamus and activity in primary somatosensory cortex (S1) using extracellular electrophysiology and genetically encoded voltage imaging.

Emerging experience-dependent dynamics in primary somatosensory cortex reflect behavioral adaptation.

Behavioral experience and flexibility are crucial for survival in a constantly changing environment. Despite evolutionary pressures to develop adaptive behavioral strategies in a dynamically changing sensory landscape, the underlying neural correlates have not been well explored. Here, we use genetically encoded voltage imaging to measure signals in primary somatosensory cortex (S1) during sensory learning and behavioral adaptation in the mouse.

Rapid Cortical Adaptation and the Role of Thalamic Synchrony during Wakefulness.

Rapid sensory adaptation is observed across all sensory systems, and strongly shapes sensory percepts in complex sensory environments. Yet despite its ubiquity and likely necessity for survival, the mechanistic basis is poorly understood. A wide range of primarily and anesthetized studies have demonstrated the emergence of adaptation at the level of primary sensory cortex, with only modest signatures in earlier stages of processing.

Compensation of physiological motion enables high-yield whole-cell recording in vivo.

Background: Whole-cell patch-clamp recording in vivo is the gold-standard method for measuring subthreshold electrophysiology from single cells during behavioural tasks, sensory stimulations, and optogenetic manipulation. However, these recordings require a tight, gigaohm resistance, seal between a glass pipette electrode's aperture and a cell's membrane. These seals are difficult to form, especially in vivo, in part because of a strong dependence on the distance between the pipette aperture and cell membrane.

Unilateral Optogenetic Inhibition and Excitation of Basal Ganglia Output Affect Directional Lick Choices and Movement Initiation in Mice.

Models of basal ganglia (BG) function predict that tonic inhibitory output to motor thalamus (MT) suppresses unwanted movements, and that a decrease in such activity leads to action selection. Further, for unilateral activity changes in the BG, a lateralized effect on contralateral movements can be expected due to ipsilateral thalamocortical connectivity. However, a direct test of these outcomes of thalamic inhibition has not been performed.

Stimulus Context and Reward Contingency Induce Behavioral Adaptation in a Rodent Tactile Detection Task.

Behavioral adaptation is a prerequisite for survival in a constantly changing sensory environment, but the underlying strategies and relevant variables driving adaptive behavior are not well understood. Many learning models and neural theories consider probabilistic computations as an efficient way to solve a variety of tasks, especially if uncertainty is involved. Although this suggests a possible role for probabilistic inference and expectation in adaptive behaviors, there is little if any evidence of this relationship experimentally.

Erratum: Genetically expressed voltage sensor ArcLight for imaging large scale cortical activity in the anesthetized and awake mouse (erratum).

[This corrects the article DOI: 10.1117/1.NPh.

Genetically expressed voltage sensor ArcLight for imaging large scale cortical activity in the anesthetized and awake mouse.

With the recent breakthrough in genetically expressed voltage indicators (GEVIs), there has been a tremendous demand to determine the capabilities of these sensors . Novel voltage sensitive fluorescent proteins allow for direct measurement of neuron membrane potential changes through changes in fluorescence. Here, we utilized ArcLight, a recently developed GEVI, and examined the functional characteristics in the widely used mouse somatosensory whisker pathway.

Biomechanical comparison of the FasT-Fix meniscal repair suture system with vertical mattress sutures and meniscus arrows.

Background: A meniscal repair technique that combines the strength of vertical mattress sutures and the decreased tissue morbidity of an all-inside technique would be advantageous.

Hypothesis: The FasT-Fix Meniscal Repair Suture System will provide load at failure, stiffness, and displacement equivalent to that of vertical mattress sutures and superior to that of Meniscus Arrows.

Study Design: In vitro biomechanical study.

Complications of tibial osteotomies in children with comorbidities.

Tibial osteotomies in children have been associated with a number of complications. A retrospective review of 116 children who had 129 tibial osteotomies was performed to assess these complications at our institution. Results showed that there were 35 cases of wound problems, 6 cases of recurrence/reoperation, 5 cases of delayed union, 2 cases with transient peroneal nerve palsy, 1 case of nonunion, and 1 case of mal-union.

Medial collateral ligament reconstruction with allograft using a double-bundle technique.

Medial collateral ligament (MCL) reconstruction has been a topic of controversy in regard to the need for surgical reconstruction as well as the type of surgical reconstruction to be performed. Combined anterior cruciate ligament (ACL) and MCL reconstruction has been found to be associated with a higher incidence of postoperative arthrofibrosis than isolated ACL reconstruction; performing these reconstructions in a staged format has been proposed to avoid this devastating complication. We present a technique for MCL reconstruction that physiometrically re-establishes both anterior and posterior stabilizing components of the MCL and is performed with a limited soft-tissue dissection.